▪ Abstract The focus of most ideas on diversity maintenance is species coexistence, which may be stable or unstable. Stable coexistence can be quantified by the long-term rates at which community members recover from low density. Quantification shows that coexistence mechanisms function in two major ways: They may be (a) equalizing because they tend to minimize average fitness differences between species, or (b) stabilizing because they tend to increase negative intraspecific interactions relative to negative interspecific interactions. Stabilizing mechanisms are essential for species coexistence and include traditional mechanisms such as resource partitioning and frequency-dependent predation, as well as mechanisms that depend on fluctuations in population densities and environmental factors in space and time. Equalizing mechanisms contribute to stable coexistence because they reduce large average fitness inequalities which might negate the effects of stabilizing mechanisms. Models of unstable coexitence...

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Mechanisms of Maintenance of Species Diversity

A new hypothesis, based on differences in the rates at which populations of competing species approach competitive equilibrium (reduction or exclusion of some species), is proposed to explain patte...

A General Hypothesis of Species Diversity

This paper is a summary and synthesis of the role of nutrients and spatial and temporal fluctuations in controlling the species composition, diversity, and seasonal succession of planktonic algal communities. We do not review the full breadth and depth of the literature that has appeared since the seminal papers by Hutchinson (34) and Dugdale (19). Rather, we focus on some of the major questions and hypotheses, and evaluate these in light of their consistency with observation and experimentation. Because the combined net effect of limiting nutrients, major ions, pH, and other physical factors ultimately determines the reproductive rate of a local algal population, we first briefly review the data on the role of these factors in phytoplankton ecology. We then review the theory of resource competition and apply it to the questions of equilibrium versus nonequilibrium approaches, seasonal succession, and multitrophic level effects in phytoplankton com-

Phytoplankton Community Ecology: The Role of Limiting Nutrients

Theoretical developments in spatial competitive coexistence are far in advance of empirical investigations. A framework that makes comparative predictions for alternative hypotheses is a crucial element in narrowing this gap. This review attempts to synthesize spatial competition theory into such a framework, with the goal of motivating empirical investigations that adopt the comparative approach. The synthesis presented is based on a major axis, coexistence in spatially homogeneous vs. heterogeneous competitive environments, along which the theory can be organized. The resulting framework integrates such key concepts as niche theory, spatial heterogeneity and spatial scale(s) of coexistence. It yields comparative predictions that can guide empirical investigations.

Competitive coexistence in spatially structured environments: a synthesis

http://eebweb.arizona.edu/Faculty/chesson/Peter/Reprints/2000_General_Theory.pdf

General Theory of Competitive Coexistence in Spatially-Varying Environments

Coexistence of species competing for shared resources.

Some mathematical problems concerning the ecological principle of competitive exclusion

Coexistence of two competitors on one resource.

http://science.sciencemag.org/content/sci/183/4123/444.full.pdf

Robert A. Armstrong

Papers

Coexistence of species competing for shared resources.

Some mathematical problems concerning the ecological principle of competitive exclusion

Coexistence of two competitors on one resource.

Dynamics of expanding inhibitory fields.

Chauncey william waggoner.